I read an article somewhere about them. They’re the airbag computers, and they record your speed, and I don’t know what else. Testimony has been given in court on some accidents as to the speed that the car was going when the airbag deployed. I think they’ve been around since the 1990’s.
Remember how Toyota technicians figured what James Sikes did to his Toyota Prius? It was a black box.... Next mandate may be add transponder (RFID) on every cars...